RNF20 promotes the polyubiquitination and proteasome-dependent degradation of AP-2α protein  

作　　者：Peng Ren Zhifeng Sheng Yijun Wang Xin Yi Qiuzhi Zhou Jianlin Zhou Shuanglin Xiang Xiang Hu Jian Zhang 

机构地区：[1]Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Science, Hunan Normal University,Changsha 410081, China [2]Institute of Metabolism and Endocrinology, The Second Xiang-Ya Hospital, Central South University, Changsha 410011, China [3]Department of Biochemistry and Molecular Biology, Changsha Medical University, Changsha 410219, China

出　　处：《Acta Biochimica et Biophysica Sinica》2014年第2期136-140,共5页生物化学与生物物理学报（英文版）

基　　金：This work was supported by the grants from the National Natural Science Foundation of China （31071150）, China Postdoctoral Science Foundation （2012M511380）, Hunan Postdoctoral Science Foundation （2012RS4016）, and E-Institutes of Shanghai Municipal Education Commission （E03003）.

摘　　要：Transcription factor activator protein 2α （AP-2α is a nega- tive regulator of adipogenesis by repressing the transcription of CCAAT/enhancer binding protein （C/EBPoz） gene. During adipogenesis, AP-2α is degraded, leading to transcriptional up-regulation of C/EBPα. However, the mechanism for AP- 2α degradation is not clear. Here, using immunoprecipitation assay and mass spectrometry, we identified ring finger protein 20 （RNF20） as an AP-2α-interacting protein in 3T3-LI preadipocytes. RNF20 has been proved to be an E3 ubiquitin ligase for both histone H2B and tumor suppressor ErbB3- binding protein 1 （Ebpl）. In this study, we demonstrated that RNF20 co-localized and interacted with AP-2α, and promoted its polyubiquitination and proteasome-dependent degrad- ation. Over-expression of RNF20 inhibited the activity of AP-2α and rescued the C/EBPα expression which was inhib- ited by AP-2α. These results suggested that RNF20 may play roles in adipocyte differentiation by stimulating ubiquitin- proteasome-dependent degradation of AP-2α.Transcription factor activator protein 2α （AP-2α is a nega- tive regulator of adipogenesis by repressing the transcription of CCAAT/enhancer binding protein （C/EBPoz） gene. During adipogenesis, AP-2α is degraded, leading to transcriptional up-regulation of C/EBPα. However, the mechanism for AP- 2α degradation is not clear. Here, using immunoprecipitation assay and mass spectrometry, we identified ring finger protein 20 （RNF20） as an AP-2α-interacting protein in 3T3-LI preadipocytes. RNF20 has been proved to be an E3 ubiquitin ligase for both histone H2B and tumor suppressor ErbB3- binding protein 1 （Ebpl）. In this study, we demonstrated that RNF20 co-localized and interacted with AP-2α, and promoted its polyubiquitination and proteasome-dependent degrad- ation. Over-expression of RNF20 inhibited the activity of AP-2α and rescued the C/EBPα expression which was inhib- ited by AP-2α. These results suggested that RNF20 may play roles in adipocyte differentiation by stimulating ubiquitin- proteasome-dependent degradation of AP-2α.

关 键 词：AP-2Α RNF20 E3 ubiquitin ligase ubiquitin-proteasome-dependent degradation C/EBPΑ 

分 类 号：Q55[生物学—生物化学] Q26